Nissan Almera starting problem?

Hi there - I have a 2002 Nissan Almera 1.6 petrol. This is the South African version but I assume the engine is basically the same around the world. Just recently the car has difficulty starting sometimes. The engine will start, but immediately cut out. If I try to start it immediately thereafter, the starter runs, but the engine won't fire. If I wait for approximately 15 seconds with the ignition off, I will hear a relay click and can then try again. Sometimes it will start on the second try, sometimes it takes ages.
I assume this is an electronic problem? Does anyone have any ideas to offer?
Thanks, Mike.